Drogba returned to Stamford Bridge as a free agent this summer after leaving Galatasaray. The Ivorian followed fellow striker Costa to west London as well as the striker's former Atletico Madrid teammate Filipe Luis and midfielder Cesc Fabregas from Barcelona.

The 36-year-old, who won three Premier League titles and the Champions League during his previous eight-year spell at the club, has backed Brazil-born Costa to make an impact in English football.

"I've been watching Diego play over the last few years and the first time I saw him I really liked him as a player," he told The Sun. "I like his character, he's solid, he can score goals and he's also technically gifted. He likes people to respect him and that's important."

Drogba added that the signing of former Arsenal captain Fabregas and Brazilian left-back Luis will add quality to Jose Mourinho's squad, which finished third in the Premier League table last season, four points behind champions Manchester City.

"It was very important for us to buy these players, they are all good signings," he said. "To have Cesc with us, I think he'll understand it's better to be with us than against us.

"They are good players and I hope they will bring their talent and experience to the team."

Fabregas and Luis come into the club following the departures of veterans Frank Lampard and Ashley Cole, and Drogba took the opportunity to pay tribute to his former teammates.

"This is the first time I've had a chance to speak about those two players that left," he said. "Ash was the best left-back in the world and I was lucky to have him in my team because when he was at Arsenal he was a difficult player to play against. He became a better player when he came to Chelsea.

"Everyone knows exactly what Frank meant to me. People say I scored a lot of goals but he was involved in almost all of them.

"The partnership with him was incredible and he's a legend at this club. I know he will also come back one day because he belongs to the Blues."